CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 5, September/October 2011
276
AFRICA
Clinically, patients with DCRV and no VSD resemble patients
with isolated pulmonary valve stenosis. When a VSD is present,
the clinical picture relates to a VSD. Usually, the patient is
diagnosed with a VSD or pulmonary outflow tract obstruction
and subsequently may show signs of progression of the outflow
obstruction, such as cyanosis, fatigue and decreased exercise
tolerance. Patients with severe right ventricle hypertension may
present with cyanosis, right ventricular failure, failure to thrive
and fatigue.
3
Four physiological groups occur, with patients presenting
usually with left-to-right shunt or the physiology of tetralogy of
Fallot.
8
Most patients are non-dysmorphic and acyanotic with
normal peripheral examinations. Auscultation reveals a vari-
able intensity of the second heart sound. A holosystolic ejection
murmur, which peaks in intensity near midsystole, with greatest
intensity at mid-left and upper-left precordial areas, characterises
a double-chambered right ventricle. A right ventricular heave,
hepatomegaly and tachypnoea indicate right ventricular hyper-
tension.
1,3,8
The chest radiograph is similar to that from other types of
right ventricular outflow tract obstruction, unless a significant
ventricular septal defect is present.
1
In most patients, the elec-
trocardiogram shows right ventricular hypertrophy but may
show evidence of diminished terminal right ventricular forces.
Two-dimensional echocardiography is usually diagnostic in
this lesion. The anomalous muscle bundles can be visualised
best from either the subcostal or parasternal views. Severity of
obstruction can be assessed by the degree of anatomical narrow-
ing and by Doppler interrogation of the obstructed region. Colour
flow Doppler identifies the site of obstruction by the appearance
of a mosaic pattern where the high-velocity flow originates. In
addition, the presence or absence of a ventricular septal defect
can be documented. Abnormal fluttering of the pulmonary valve
is often a concomitant finding.
1,9
Cardiac catheterisation is sometimes performed to confirm
the diagnosis of a double-chambered right ventricle. The cath-
eter must be placed in the inflow portion of the right ventricular
cavity, and a pressure gradient is demonstrated as the catheter is
farther advanced into the distal, low-pressure chamber. The pres-
sure in the distal chamber is usually equal to that in the pulmo-
nary artery unless there is associated pulmonary valve stenosis.
Care must be taken first to place the catheter into the right
ventricular apex, because it is relatively easy to advance the cath-
eter from the right atrium directly to the right ventricular outflow
tract and measure the gradient. If a ventricular septal defect is
present, the location and resultant shunt should be determined.
1,8,9
Right ventricular angiography is the best tool for accurate
diagnosis of this lesion and should always be performed when
a significant intra-ventricular pressure gradient is detected.
Anterior and lateral projections demonstrate filling defects with-
in the right ventricle below the crista supraventricularis, between
the outflow and inflow areas. Left ventriculography should
also be performed to determine whether there is an associated
ventricular septal defect or, less commonly, sub-aortic stenosis.
8
The role of magnetic resonance imaging (MRI) as a diagnos-
tic tool in congenital heart disease has increased significantly
over the past decade.
10
Its role is particularly important in adult
patients in whom echocardiographic views are often limited, and
who can best cooperate with the testing requirements of MRI
to obtain optimal images. The anatomical features of a double-
chambered right ventricle can be readily recognised by MRI,
10
and it is even possible to obtain a quantitative assessment of
the severity of obstruction by measuring flow velocities. MRI is
likely to be superior to echocardiography in the older patient and
may obviate the need for cardiac catheterisation in most patients.
10
The natural history varies depending on the presence of asso-
ciated lesions. Progressive obstruction of the right ventricular
outflow tract has been observed and can lead to right ventricular
failure, especially in the presence of a VSD. Several physicians
report diagnosis in asymptomatic adults in whom anomalous
muscle bundles and an intact ventricular septum may have been
associated with a VSD that underwent spontaneous closure.
3
Surgical resection of the bundle, as well as repair of other anom-
alies is usually indicated as soon as the diagnosis is made.
1,3,8,9,11,12
In the absence of a significant associated lesion, observation may
be appropriate as long as the intra-cavitary gradient is not greater
than 40 mmHg and the degree of obstruction is not progressive.
The time to intervene naturally depends on the associated
lesions. The current practice is to address associated lesions
(ventricular septal defect, sub-aortic stenosis, pulmonary steno-
sis) at the time of DCVR repair. Drug therapy is not currently a
component of the standard of care for DCVR.
3
Treatment is by surgical resection of the anomalous muscle
bundles. Long-term follow up is as with only mild residual
sequel such as tricuspid regurgitation. The need for re-operation
for recurrent obstruction is exceedingly uncommon.
Fatalities reported in the surgical literature are rare. A recent
series reports no hospital or late deaths. Much of the reported
morbidity and mortality result from a failure to diagnose the
DCRV. This failure has pre-operatively led either to closure of
one of the portions of the right ventricle, with a fatal outcome,
or to re-operation in cases where the VSD was closed, although
an obstructed right ventricle remained.
3,8-11
In the larger series,
residual mild right ventricular outflow tract obstruction, non-
haemodynamically significant residual VSDs, tricuspid valve
regurgitation, and aortic valve regurgitation have been described
as long-term morbidity issues.
3,13,14
References
1.
Lourdes RP, Larry AL. Pulmonary stenosis. In: Allen HD, Driscoll DJ,
Shaddy RE, Feltes TF, eds.
Moss and Adams’ Heart Disease in Infants,
Children, and Adolescents: Including the Fetus and Young Adults
.
Lippincott: Williams & Wilkins, 2008: 847–848.
2.
Romano MMD, Furtado RG, Dias CGF, Jurca M, Almeida-Filho OC,
Maciel BC. Double-chambered right ventricle in an adult patient diag-
nosed by transthoracic echocardiography.
Cardiac Ultrasound
2007;
5
(2): 1476–7120-5-2.
3.
Sanatani S, Peirone AR. Double-chambered right ventricle. eMedicine
Specialties. Pediatrics; Cardiac Disease and Critical Care Medicine:
Cardiology.
4.
Restivo A, Cameron AH, Anderson RH, Allwork SP. Divided right
ventricle: a review of its anatomical varieties.
Paediatr Cardiol
1984;
5
(3): 197–204.
5.
Byrum CJ, Dick M, Behrendt DM. Excitation of the double chamber
right ventricle: electrophysiologic and anatomic correlation.
Am J
Cardiol
1982;
49
(5): 1254–1258.
6.
Hubail CJ, Ramaciotti C. Spatial relationship between the ventricular
septal defect and the anomalous muscle bundle in a double-chambered
right ventricle.
Congenit Heart Dis
2007;
2
(6): 421–423.
7.
Vogel M, Smallhorn JF, Freedom RM. An echocardiographic study of
the association of ventricular septal defect and right ventricular muscle
bundles with affixed subaortic abnormality.
Am J Cardiol
1988;
61
(10):
